Introduction to Basic Manufacturing Processes and ... - always yours

Front brace
Milling 453
It is an extra support, which is fitted between the knee and the over-arm to ensure
further rigidity to the arbor and the knee.
Spindle
It is situated in the upper part of the column and receives power from the motor through
belts, gears. and clutches and transmit it to the arbor.
Arbor
It is like an extension of the machine spindle on which milling cutters are securely
mounted and rotated. The arbors are made with taper shanks for proper alignment with the
machine spindles having taper holes at their nose. The draw bolt is used for managing for
locking the arbor with the spindle and the whole assembly. The arbor assembly consists of
the following components.
1. Arbor 2. Spindle
3. Spacing collars 4. Bearing bush
5. Cutter 6. Draw bolt
7. Lock nut 8. Key block
9. Set screw
24.5.2 Planer Type Milling Machine
It is a heavy duty milling machine. It resembles a planer and like a planning machine
it has a cross rail capable of being raised or lowered carrying the cutters, their heads, and
the saddles, all supported by rigid uprights. There may be a number of independent spindles
carrying cutters on the rail as two heads on the uprights. The use of the machine is limited
to production work only and is considered ultimate in metal re-moving capacity.
24.5.3 Special Type Milling Machines
Milling machines of non-conventional design have been developed to suit special purposes.
The features that they have in common are the spindle for rotating the cutter and provision
for moving the tool or the work in different directions.
24.6 SIZE OF MILLING MACHINE
The size of the column and knee type milling machine is specified by
(1) The dimensions of the working surface of the table, and
(2) Its maximum length of longitudinal, cross and vertical travel of the table.
In addition to above, number of spindle speeds, number of feeds, spindle nose taper,
power available, floor space required and net weight of machine will also be required for
additional specification.
24.7 DEPTH OF CUT
The depth of cut in milling is defined as the thickness of the material removed in one
pass of the work under the cutter. Thus it is the perpendicular distance measured between
the original and final surface of the workpiece, and is expressed in mm.